The federal child care subsidy program (the Child care and Development Fund [CCDF]) is among the government's largest investments in the early care and education (ECE) of low income children, yet associations between CCDF-subsidized care use and children's developmental outcomes are poorly understood. These findings raise unanswered questions about the specific ECE teacher and classroom characteristics in programs that serve subsidized children, and how variation in those teacher and classroom-specific features may give rise to variation in child outcomes. Using three recent nationally representative data sets, this project will address the following questions: What were the cognitive and social-emotional school readiness gaps at kindergarten entry in 2011 between children whose pre-kindergarten year ECE was funded with CCDF subsidies and children whose pre-kindergarten year ECE was not funded with CCDF subsidies, and have these gaps narrowed, widened, or remained stable since 2006-2007? Are there differences in workforce characteristics (caregiver knowledge, skills, attitudes, experience, and compensation) between ECE providers serving subsidized versus unsubsidized children? Are there differences in classroom characteristics (materials, activities, instructional time and context) between ECE providers serving subsidized versus unsubsidized children? Are associations between subsidy status and school readiness mediated by the workforce and classroom characteristics examined in Questions 2 and 3? Across all questions, this study will consider three different conceptualizations of unsubsidized status (private pay; free, other publicly-funded care such as Head Start and public pre-k; and both). This study will also consider contrasts within and between different types of care settings (center versus home). Findings will be particularly informative to states and policymakers as they determine how to spend funds earmarked for quality improvement within the Child care and Development Block Grant legislation. Results will point to specific aspects of subsidized children's classroom experiences that might be well suited for quality improvement initiatives.